Radio Frequency Bands for Railways

Questions and Answers

What is the frequency of inspecting the Systems and communication media installed inside the tunnels?

Weekly

Yearly

Quarterly

Monthly (correct)

How often should the Master unit be checked for any fault alarm(s)?

Monthly

Quarterly

Weekly (correct)

Daily

What is the purpose of the Reference screen shot prepared when the complete system is in satisfactory working condition?

To record system configurations

To troubleshoot system failures

To provide a baseline for future troubleshooting (correct)

To train new maintenance personnel

What is the tool used to measure the power of optical signals?

Optical power meter Signup and view all the answers

How often should the Integrated Digital PA System be inspected?

Monthly Signup and view all the answers

What is the purpose of the three handheld radios programmed with the working frequencies?

To establish emergency communication Signup and view all the answers

Who should the System's failure be reported to daily in the morning?

The controlling officer Signup and view all the answers

What is the purpose of the Fibre splicing machine?

To splice fibre optic cables Signup and view all the answers

What is the frequency band allotted for VHF Simplex communication in Indian Railways?

146-163MHz Signup and view all the answers

What type of communication system is used for communication between driver, guard, station master, and cabin during emergency situations?

VHF Simplex Signup and view all the answers

What is the frequency band recommended for LTE in Indian Railways?

700MHz Signup and view all the answers

What type of tunnel communication system is required for tunnels with a length of more than 5 Km?

Radio Communication System Signup and view all the answers

What is the primary function of the Tunnel Radio System?

To provide uninterrupted radio communication inside a tunnel Signup and view all the answers

What is the frequency band allotted for LocoTrol in Indian Railways?

424-430MHz Signup and view all the answers

What is the purpose of the Railway Telecom Manual?

To provide guidelines for tunnel communication system Signup and view all the answers

What is the main requirement of the tunnel communication system in Indian Railways?

To provide communication need to the tunnels of varying lengths Signup and view all the answers

What is the primary reason for installing loudspeakers every 100m in the tunnel?

To inform and warn maintenance and service staff in abnormal conditions Signup and view all the answers

Where should hotline telephone services be extended to?

Tunnel Maintenance Boxes and Central Tunnel Control Room Signup and view all the answers

What is the primary purpose of the IP-based Video Surveillance System in tunnels?

To ensure there are no blank spots over the tunnels Signup and view all the answers

How often should the transmitting frequency and power of the system be checked?

Monthly Signup and view all the answers

What aspect of the Power Supply System should be checked weekly?

Input and output voltage & currents Signup and view all the answers

How often should the Antenna system along with Radiating cable and connectors be physically checked?

Weekly Signup and view all the answers

Where are the camera feeds transferred to for viewing, recording, and monitoring of tunnels?

All of the above Signup and view all the answers

What is the primary requirement for the camera performance inside the tunnels?

Good performance in low light scenarios Signup and view all the answers

What is the frequency band allocated for TCAS in Indian Railways?

405-512 MHz Signup and view all the answers

What is the primary purpose of the Tunnel Radio System?

To provide uninterrupted radio communication inside tunnels with the headquarters and operation centers Signup and view all the answers

What is the minimum length of tunnels where the Master Unit system is required?

500 meters Signup and view all the answers

What is the function of the Optical Remote Unit in the Tunnel Communication System?

To convert optical signals to RF signals Signup and view all the answers

What is the frequency band allocated for TETRA in Indian Railways?

370-430 MHz Signup and view all the answers

What is the primary requirement of the Tunnel Radio System in Indian Railways?

Interruption-free radio communication Signup and view all the answers

What is the purpose of the Master Unit in the Tunnel Communication System?

To convert signals from RF to light when fibre fed repeaters is used Signup and view all the answers

What is the document that provides guidelines for railway communication in India?

Indian Railways Telecom Manual Signup and view all the answers

What is the primary function of the Off-Air Channelized Repeater in tunnel communication systems?

To amplify radio signals for VHF Simplex, LocoTrol, GSM-R/LTE, TETRA and TCAS communication Signup and view all the answers

What type of cable is used for wireless communication inside tunnels to minimize smoke accumulation in case of fire?

7/8" Leaky Cable Signup and view all the answers

What is the purpose of the Optical Remote Unit in tunnel communication systems?

To provide coverage in tunnels more than 500 meters Signup and view all the answers

What is the primary characteristic of a 7/8" Leaky Cable?

It has gaps or slots in its outer conductor Signup and view all the answers

Where are antennas installed for tunnels more than 500 meters?

On a tower Signup and view all the answers

What is the purpose of the Fibre Junction Box in tunnel communication systems?

To connect the Master Unit to the tunnel optical remote unit Signup and view all the answers

What is the primary application of the Off-Air Channelized Repeater in tunnel communication systems?

For wireless communication in tunnels less than 500 meters Signup and view all the answers

Which of the following communication systems is mentioned in the Indian Railways Telecom Manual - 2021?

All of the above Signup and view all the answers

What is the primary purpose of using Leaky Cable Systems in tunnel communication?

To minimize accumulation of smoke inside the tunnel in case of accidental fire Signup and view all the answers

What is the maximum length of tunnels that can be covered using High Gain Off-Air Channelized Repeaters?

Less than 500 meters Signup and view all the answers

What is the primary function of Optical Remote Units in tunnel communication systems?

To relay signals from the Master Unit to the tunnel Signup and view all the answers

Where are antennas installed for tunnels more than 500 meters?

On a Tower Signup and view all the answers

What is the primary characteristic of a 7/8" Leaky Cable?

It has gaps or slots in its outer conductor Signup and view all the answers

What is the purpose of the Fibre Junction Box in tunnel communication systems?

To connect the Master Unit to the Optical Remote Unit Signup and view all the answers

What is the primary application of the Off-Air Channelized Repeater in tunnel communication systems?

To provide coverage in tunnels with lengths less than 500 meters Signup and view all the answers

What type of cable is used for wireless communication inside tunnels to minimize smoke accumulation in case of fire?

FRLS-0H rated Leaky Cable Signup and view all the answers

What is the primary function of the Master Unit in the Tunnel Communication System?

To convert RF signals to light signals Signup and view all the answers

What is the primary function of the Optical Remote Unit in the Tunnel Communication System?

To convert light signals to RF signals Signup and view all the answers

Where are antennas installed for tunnels more than 500 meters?

Along the Leaky cable in the tunnel Signup and view all the answers

What type of cable is used for wireless communication inside tunnels to minimize smoke accumulation in case of fire?

Leaky cable Signup and view all the answers

What is the primary application of the Off-Air Channelized Repeater in tunnel communication systems?

To amplify weak RF signals Signup and view all the answers

What is the primary characteristic of a 7/8" Leaky Cable?

It is used for wireless communication Signup and view all the answers

What is the purpose of the Fibre Junction Box in tunnel communication systems?

To connect fibre optic cables Signup and view all the answers

What is the frequency band allocated for TETRA in Indian Railways?

370-430 MHz Signup and view all the answers

What is the frequency of checking the EC socket?

Weekly Signup and view all the answers

What is the purpose of the Line Tester?

To detect faults in the communication system Signup and view all the answers

Who is responsible for inspecting all Systems and communication media installed inside the tunnels?

SSE/JE/TELE Signup and view all the answers

What is the purpose of the Digital Multimeter?

To detect faults in the communication system Signup and view all the answers

How often should the Video Surveillance System be inspected?

Monthly Signup and view all the answers

What is the purpose of the connecting cables supplied along with the system?

To connect the Laptop/PC to the Master unit Signup and view all the answers

What is the purpose of the Reference screen shot prepared when the complete system is in satisfactory working condition?

To keep a record of the system's satisfactory working condition Signup and view all the answers

How often should the Hotline Telephone Services & Regular Railway Telephone be inspected?

Monthly Signup and view all the answers

What is the primary purpose of installing loudspeakers every 100m in the tunnel?

To inform and warn maintenance and service staff during incidents Signup and view all the answers

What is the primary requirement for the camera performance inside the tunnels?

To perform well in low light scenarios Signup and view all the answers

Where are the camera feeds transferred to for viewing, recording, and monitoring of tunnels?

Both A and B Signup and view all the answers

What is the primary purpose of the IP-based Video Surveillance System in tunnels?

To ensure there are no blank spots over the tunnels Signup and view all the answers

How often should the transmitting frequency and power of the system be checked?

Once in a month Signup and view all the answers

What aspect of the Power Supply System should be checked weekly?

Input and output voltage & currents Signup and view all the answers

How often should the Antenna system along with Radiating cable and connectors be physically checked?

Weekly Signup and view all the answers

Where should hotline telephone services be extended to?

Tunnel Maintenance Boxes Signup and view all the answers

What is the purpose of the Optical Remote Unit in tunnel communication systems?

To extend the coverage area of the tunnel communication system Signup and view all the answers

Where are antennas installed for tunnels more than 500 meters?

Near the Fibre Junction Box Signup and view all the answers

What is the primary application of the Off-Air Channelized Repeater in tunnel communication systems?

To extend the coverage area of the tunnel communication system Signup and view all the answers

What type of cable is used for wireless communication inside tunnels to minimize smoke accumulation in case of fire?

Leaky Cable Signup and view all the answers

What is the primary characteristic of a 7/8" Leaky Cable?

Radiates signal along its length Signup and view all the answers

What is the purpose of the Fibre Junction Box in tunnel communication systems?

To manage fibre optic cables for tunnels more than 500 meters Signup and view all the answers

What is the purpose of the sound hood in Emergency Telephones?

To avoid noise-affecting conversation Signup and view all the answers

Where should Emergency Telephones be installed in tunnels?

On tunnel walls and escape walkways Signup and view all the answers

Study Notes

Tunnel Communication System

The Indian Railways Telecom Manual 2021 outlines the requirements for tunnel communication systems.
The system is necessary for communication during maintenance and constructional blocks, train operation, and emergency situations.

Frequency Bands

VHF Simplex: 146-163MHz
LocoTrol: 424-430MHz
GSM-R/LTE: 876-915MHz (Uplink) and 921-960MHz (Downlink), with 700MHz recommended for LTE
TCAS: 405-512MHz
TETRA: 370-430MHz

Master Unit

Used to convert RF signals to light for fibre-fed repeaters
May consist of:
- Channelized VHF Simplex Off-Air Repeater and VHF Simplex Optical Master Unit
- GSM-R/LTE Off-Air Repeater and GSM-R/LTE Optical Master Unit
- Channelized TCAS/LocoTrol/TETRA Off-Air Repeater and TCAS/LocoTrol/TETRA Optical Master Unit

Optical Remote Unit

Used to convert optical signals to RF signals for wireless communication in the tunnel
Connected to the Master Unit
Accepts VHF Simplex, LocoTrol, GSM-R/LTE, TETRA, and TCAS signals

System Maintenance

Check Master Unit for faults on a weekly basis
Check power supply system, including input and output voltage, current, and specific gravity of each cell on a weekly basis
Physically inspect antenna system, radiating cable, and connectors on a weekly basis
Inspect all systems and communication media installed inside tunnels on a monthly basis

Failure Report

Report system failures to the controlling officer on a daily basis
Submit a monthly report of failures to the Headquarter

Tools and Plant Required for Maintenance

Optical power meter
Hydrometer
Digital multimeter
Line tester
Fibre splicing machine
Basic tools like screwdrivers and spanner sets
Three handheld radios programmed with the working frequencies
Reference screen shot prepared when the complete system is in satisfactory working condition
A laptop
Connecting cables supplied along with the system

Tunnel Communication System

The tunnel communication system provides uninterrupted radio communication inside the tunnel with the headquarters and operation centers, and handheld devices of the tunnel operator's staff, emergency staff, and trains passing through the tunnel.

Remote Unit

The remote unit is monitored, controlled, and alarmed remotely from the master unit over fiber and remotely using an Ethernet modem.
Optical remote units are used to provide coverage in more than 500 meters length tunnels.

Off-Air Channelized Repeater

High gain off-air channelized repeaters are used to cover tunnels less than 500 meters in length.
The repeaters cover VHF simplex, LocoTrol, GSM-R/LTE, TETRA, and TCAS communication per bore.

Leaky Cable

Leaky cable is used for wireless communication inside the tunnel.
FRLS-0H (Flame retardant Low Smoke Zero Halogen) rated leaky cable is used to minimize smoke accumulation in case of accidental fire.
Two 7/8" leaky cables are used per tunnel tube length for VHF simplex, LocoTrol, GSM-R/LTE, TCAS, and TETRA communication.

Antenna for System

Antennas are installed at tunnel sites for tunnels less than 500 meters.
Antennas are installed on a tower for tunnels more than 500 meters.
The wireless system and tower with antenna should have SACFA clearance.

Optic Fibre Cable

The master unit at the base station is connected to the tunnel optical remote unit through a fibre junction box.

TCAS and TETRA

Frequency bands 405-512 MHz are allotted for TCAS in Indian Railways.
Frequency bands 370-430 MHz are allotted for TETRA in Indian Railways.

Master Unit

The master unit is used to convert signals from RF to light when fibre-fed repeaters are used at the remote end of the optical link.
The master unit system consists of channelized VHF simplex off-air repeater and VHF simplex optical master unit, GSM-R/LTE off-air repeater and GSM-R/LTE optical master unit, and channelized TCAS/LoCoTrol/TETRA off-air repeater and TCAS/LoCoTrol/TETRA optical master unit.

Optical Remote Unit

The optical remote unit is used to convert optical signals to RF signals and transmit them into the leaky cable in the particular area to cover the tunnel for wireless communication.
The optical remote unit is connected to the master unit and accepts VHF simplex, LocoTrol, GSM-R/LTE, TETRA, and TCAS.

Public Addressing System

A public address system is provided to inform/warn maintenance and service staff, and give instructions to people in abnormal conditions during incidents.
Loudspeakers are installed every 100 meters in the tunnel.
The PA system should be installed at more than 500 meters tunnel lengths.

Hotline Telephone

Hotline telephone services should be extended to tunnel maintenance boxes.
These services should be connected to the central tunnel control room/divisional control room.
Regular railway telephone services should be extended to tunnel maintenance boxes at appropriate locations.

Control and Monitoring System

IP-based video surveillance system should be provided inside tunnels to ensure there are no blank spots.
The camera should perform well in low light scenarios inside the tunnel.
All camera feed should be transferred to the tunnel control center/divisional control room for viewing, recording, and monitoring of tunnels through cameras.

Maintenance of System

Transmitting frequency and power of the system should be checked once a month.
Power supply system should be checked weekly.
Antenna system along with radiating cable and connectors should be physically checked weekly.
Master unit fault alarms should be checked weekly.
Emergency communication (EC) socket should be checked weekly.
Hotline telephone services and regular railway telephone should be checked monthly.
Integrated digital PA system and video surveillance system should be checked monthly.

Inspection

All systems and communication media installed inside the tunnels should be inspected every month by SSE/JE/TELE.

Failure Report

System failure should be reported to the controlling officer daily in the morning.
A monthly statement of failure should be reported to the PCDO to headquarters.

Tools and Plant Required for Maintenance of Equipment

Optical power meter
Hydrometer
Digital multimeter
Line tester
Fibre splicing machine
Basic tools like screwdrivers and spanner sets
Three handheld radios programmed with the working frequencies
Reference screen shot prepared when the complete system is in satisfactory working condition
A laptop
Connecting cables supplied along with the system

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Description

This quiz covers the radio frequency bands allotted for TCAS and TETRA in Indian Railways, as well as the Tunnel Radio System for uninterrupted communication.